Environmental Enrichment And Pig Welfare
Animal welfare is defined by how an animal’s surroundings affect their physical and mental health. In factory farms, pig welfare is, obviously, very low: along with commonly suffering abuse and neglect, they live in cramped, bare spaces where they can’t express any of their natural behaviors.
One of the best ways to improve pigs’ welfare is to provide them with plenty of environmental enrichment. To be most effective, any enrichment objects should be cleaned and replaced often, provide some aspect of novelty, and be accessible to all pigs. The objects used to improve pigs’ lives fall into three categories based on their effectiveness: optimal, suboptimal, or material of marginal interest.
A lack of proper environmental enrichment leads pigs to become aggressive and display repetitive, obsessive behavior called “stereotypies,” such as biting and pacing. Pigs will use stereotypies as a distraction to cope with their horrifying surroundings—they’ve been known to bite the bars on their cage for hours without rest. Rather than fixing the root cause of these problems, however, most factory farms use superficial “solutions” to change pigs’ behavior. For example, rather than providing pigs with more space so they’ll stop biting each other’s tails, it is a common practice to cut the pigs’ tails off instead.
In this literature review, researchers looked at nearly a hundred different research papers to find the best forms of environmental enrichment for pigs. They found that the following methods of enrichment made pigs happier, more social, less aggressive, and less likely to display stereotypies.
The first and most important environmental enrichment strategy was giving pigs as much space as possible. One of the studies in the review found that corticosteroid levels, which indicate how stressed a pig is, were consistently higher in densely populated pens, even when the smaller pens were filled with bedding and toys. It also found that pigs were less aggressive and more interested in their surroundings when they had more space.
A close second for improving pigs’ welfare was providing them with fresh straw. Enough straw bedding allows pigs to express natural behaviors like rooting, chewing, and manipulating their surroundings. Pigs with access to straw were happier in almost every way: they were more playful, less aggressive, and less likely to display stereotypies like tail biting.
Hanging toys were not nearly as effective as straw with one major exception: hanging pieces of freshly cut birch trees. These hanging pieces of wood attracted the pigs more than any other form of enrichment, and drastically reduced stress-based activities like tail biting.
Environmental enrichment doesn’t always need to be physical. For example, one study in the review found that pigs preferred blue lighting to other colors, and that playing classical music made them more active. The most effective non-physical enrichment, however, seems to be aroma: pigs with access to natural smells like thyme, fresh grass, and moist soil were far less aggressive than the pigs without access to these fragrances.
All of these methods work best when they are used together. Although suboptimal materials like shredded paper, rope, and peanut shells don’t improve pigs’ welfare much on their own, they can be more powerful when combined with optimal enrichment materials. The same is true of materials of marginal interest like chains, rubber, and hardwood.
No matter how effective the method of enrichment is, its benefits stop if the item is not consistently provided. For example, one of the studies found that when pigs could only access toys at certain times each day, they became even more stressed than pigs without any enrichment at all. Much like when a child’s toy is taken away, the pigs become sad when they lose access to these materials. The same study also found that when there were not enough materials for all of the pigs to use, they started to fight over them, causing them to become even more stressed and aggressive.
While this literature review shows some promising results in improving pigs’ lives on farms, it’s important to note that improving welfare should not substitute for reducing our consumption of these amazing animals. The goal of this review wasn’t to improve welfare for the animals solely out of compassion, but to stop pigs from engaging in “unprofitable” activities like fighting. Ensuring welfare is a crucial point in the fight for pigs’ rights, but the best way to help animals is to stop eating them.